The invention relates to therapeutic beds, and more particularly, to hospital beds for use by chronic patients, such as patients who are partially or fully paralyzed, patients suffering from head injuries, from multiple sclerosis, fractured spines, and similar serious injuries, which either render the patient incapable of voluntary movement or necessitate restriction of their movements.
When a formerly normal, active person is confined to bed because of illness or injury, reduction in normal exercise produces such problems as constipation, muscle wasting, bone decalcification and bed sores. In addition, if the patient through paralysis, loss of consciousness or loss of sensitivity to pain, fails to turn themselves or shift their weight in bed with a minimum frequency, threatening complications such as hypostatic pneumonia, venous thrombosis in the lower limbs, and ducubiti may result.
The greatest portion of the human body is muscle and bone and movements such as walking, running, climbing and physical work is very important to the maintenance of a healthy human organism. The human body improves with use and deteriorates with lack of exercise. In humans, there is a minimum degree of activity below which serious degeneration results. In fact, movement of the human body is of such fundamental importance that even during sleep a normal healthy adult changes his position on an average of every eleven and a half (11.5) minutes.
So far as known, prior art hospital beds have several inherent deficiencies that are overcome by the present invention. For example, U.S. Pat. No. 3,434,165 discloses an intensive care therapeutic bed for treating acute patients requiring constant attention and personal care. It is also possible that this bed could be utilized for the treatment of chronic patients not requiring constant attention and treatment. The bed is provided with a patient supporting platform comprising a plurality of hatches to enable an attendant to gain access to all parts of a patients body for the purpose of treatment and manipulation of the individual limbs. The patient support platform is mounted for control of oscillatory movement relative to a bed support means. In order to allow the hatches to swing open, it was necessary to provide structural support for the patient support means by use of a U-shaped structural keel which transmitted the load of the patient support platform to the pivot points at each end of the bed support platform, thereby enabling the hatches to be swung down unencumbered by any underlying support member. The weight of the keel extending below the longitudinal center line of the patient support platform acted as a counterbalance in the same manner as the keel of a sailboat to prevent the bed from tipping over when the patient support platform with the patient thereon was rotated to an extreme position.
As a patient progresses from the acute to the chronic stage, the requirement for stringent mobilization is less essential and a simpler type of hospital bed than that disclosed in U.S. Pat. No. 3,434,165 can be desirably used. The plurality of hatches with the patient support platform may be reduced leaving only a rectal hatch, thus eliminating the requirement of a continuous longitudinally extending U-shaped structural support keel. However, the requirement for continuous oscillatory movement of the patient support platform is perhaps even intensified. Since the patient is not receiving constant personal attention from an attendant, and in many instances might be confined to their own home, it is most important that the patient support platform function as reliably and trouble free as possible. The present invention is intended to satisfy this requirement and in this regard, it is of utmost importance that the patient support platform oscillate continuously to the full extent of its rotating arc with minimum energy usage and motor wear. When a patient is left unattended for long periods of time, it is also essential that a greater factor of safety from tipping of the bed be provided. Since the patient is not completely immobilized and must therefore be moved from the bed more frequently for various treatments and the like, it is desirable that the attendant be able to maneuver the patient from the platform with relative ease and without assistance.